Passenger vehicles often include electric batteries for operating a vehicle's electrical and drivetrain systems. For example, vehicles commonly include a 12V lead-acid automotive battery configured to supply electric energy to vehicle starter systems (e.g., a starter motor), lighting systems, and/or ignition systems. In electric, fuel cell (“FC”), and/or hybrid vehicles, a high voltage (“HV”) battery system may be used to power electric drivetrain components of the vehicle (e.g., electric drive motors and the like).
The capacity of a battery system included in an electric vehicle (“EV”) and plug-in hybrid electric vehicle (“PHEV”) may constrain the range of the vehicle. A battery system's state of health (“SOH”) is a qualitative measure of a battery's ability to store and deliver electrical energy, while a battery system's state of charge (“SOC”) is an estimate of electrical energy stored in the battery. Battery diagnostic and prognostic methods may be used to maintain proper battery operation and to provide a user with an indication of when the battery will become depleted. Battery diagnostics may track the degradation of battery's performance to estimate battery SOH and may track the SOC. Operation of a battery system is dynamic and performance of a battery system varies with age and operating conditions. For example, the capacity of a battery may degrade over the life of the battery.